More than half a year after disclosures of systemic problems at Walter Reed Army Medical Center and other military hospitals, the Pentagon's promised fixes are threatened by staff shortages and uncertainty about how best to improve long-term care for wounded troops, according to a congressional report issued yesterday.

Army units developed to shepherd recovering soldiers lack enough nurses and social workers, and proposals to streamline the military's disability evaluation system and to provide "recovery coordinators" are behind schedule, according to the Government Accountability Office report.

Members of a congressional oversight committee, discussing the report at a hearing yesterday, said the effort to reform the medical bureaucracy has itself become mired in bureaucracy.

"After so many promises but so little progress, we need to see more concrete results," said Rep. Thomas M. Davis III (Va.), the ranking Republican on the panel. His staff hears "appalling stories" every week from soldiers dealing with the disability process, he said, adding that "they're trapped in a system they don't understand and that doesn't understand them."

"The pace of change is frustratingly slow," said Rep. Henry A. Waxman (D-Calif.), chairman of the oversight committee. "Still the horror stories continue."

Members of the House oversight subcommittee on national security laid the blame on the Defense Department, the Army and the Department of Veterans Affairs for what Rep. John F. Tierney (D-Mass.) termed an "utter lack of urgency."

The preliminary GAO report said the Army has taken steps to streamline its disability evaluation process, which determines whether soldiers are fit for duty and, if not, what disability payments they should receive. Nonetheless, the report noted, "Many challenges remain, and critical questions remain unanswered."

For example, the Army has established "warrior transition units" at 32 installations around the country, with recovering soldiers assigned to a team of physicians, case managers and squad leaders. Whereas the unit at Walter Reed is almost fully staffed, more than half the units had less than 50 percent of workers in place by mid-September, the GAO found.

Maj. Gen. Eric B. Schoomaker, the Walter Reed commander, told the subcommittee that the units have 65 percent of their manpower and should be fully staffed by January.

In July, a presidential commission led by former senator Robert J. Dole and former health and human services secretary Donna E. Shalala recommended that "recovery coordinators" be assigned to shepherd each seriously wounded service member through medical care. A high-level oversight committee established by the Pentagon and the VA agreed to begin implementing the recommendation by mid-October.

But the oversight committee has not determined how many recovery coordinators will be needed or how to decide which injured soldiers need them, the GAO found.

Moreover, the Dole-Shalala commission recommended that the recovery coordinators come from outside the Defense Department or the VA, suggesting instead the Public Health Service.

The oversight committee has balked at the suggestion in favor of recovery coordinators supplied by the VA. But the GAO questioned the beleaguered VA's ability to handle the job, noting that it "may face significant human capital challenges in identifying and training individuals for these positions."

A slew of commissions and task forces have agreed that at the heart of the bureaucratic maze is a system in which the military services and the VA evaluate injured service members. The often-conflicting evaluations leave many recovering soldiers in limbo for months or even years.

A pilot program to establish a single joint system was slated to begin Aug. 1. But the date slipped as the Pentagon and the VA reviewed options.

Michael L. Dominguez, a deputy undersecretary of defense, testified that a pilot program was approved this week but probably would not begin evaluating wounded soldiers until January.

"We're seven months into this process, and we're just now getting off the ground," Tierney said. "Why has it taken so long?"

Dominguez responded that the Pentagon and the VA needed to exercise "due diligence" before plunging forward with fundamental changes. "It does take some time to develop those details," he said.

Members of the panel sharply criticized Walter Reed for the hospital's handling of the case of Staff Sgt. John Daniel Shannon, who testified before the panel in March about his more than two years spent navigating the disability system. The Washington Post reported this month that a paperwork glitch further delayed his retirement. Schoomaker said the problem has been resolved, but panel members described the episode as highly troubling, given the public prominence of Shannon's case.